Modular Cnc Machine Tools Based On Finite Element Analysis Of Structural Dynamic Design

NC machine tool, as elementary device in the automatic manufacture, are generally applied in defense and aerospace fields, and other economy fields, then have essential effect on safety of state and development of industries. To our country, however, owing to the lag of dynamic optimal design of NC machine tools, NC machine tools having the properties of high manufacturing speed, high rigidness and high accuracy, can't be in time designed in response to market requirement.According to modern design theory, the process of mechanic production design by CAD/CAE technology omit the procedures of prototype trial manufacture, test and modification again and again. Moreover, by the virtual prototyping technology, the dynamic performances of NC are improved, and the cycle of NC analysis, design and optimization is abridged. So design cost is saved.This thesis, first, reviewed the development and present situation of the fields correlative with NC dynamic design, indicated the target and values of the thesis, and stated the chief research content of it.Second, in order to come off rapid-response design, as essential requirement of NC design, unit structures (US) and basic frames (BF), which have independent functions, are separated from main components of NC machine tools. Methods and procedures on the dynamic optimal design (DOD) of US and BF were studied, and expanded to the DOD of main components of the machine tools. Third, using the powerful FEA software, ANSYS, it was studied how to construct the modules with high dynamic performances for NC machine tools on the foundation of the DOD theory of US and BF sizes; And the DOD of the bed of NC machine tools and gantry columns were successfully accomplished, which prove that the DOD theory of US and BF is feasible and efficient.Forth, the modelization of the joint bolts was studied with respect to CONTACT49, and the modeling method was applied in the contact surface between the columns and bed of vertical manufacture center; The influence on dynamic performances of machine tools, which results from those contact surface parameters, was analyzed.Fifth, by ANSYS, the idea combining FEA with DOD was used for the DOD of mechanic structures, and took good effect in application of the DOD of gantry columns of NC machine tools. Sixth, low-order natural frequency has being obtained by the mode analysis experiment of machine tools, the dynamic parameters of combination surface jointed by bolts were identified by the synthesis of FEA, optimal algorithm and harmonic response analysis.